Detecting row selection in a QTableView

[scarleton]

How does a QTableView signal/notify that the whole row has been selected and unselected? Not just a cell, but when the user clicks on the 'virtual row header' which is to the left of the first cell in the row.

The goal is this: when a user selects a whole row, enable a button on the form which will allow the user to act upon the selected row. It is also important to know when no row is selected, so the button is not enabled.

Might there be some way to wire this up between the QTableView's model and the button?

Sam

[waynew]

This works for me

connect(view, SIGNAL(clicked(const QModelIndex&)), this, SLOT(recordSelected()));
 
//then
void MainWindow::recordSelected()
{
   QModelIndex index = view->currentIndex();
   QSqlRecord record;
   int i = index.row(); // now you know which record was selected
   record = model->record(i);
// and I do something with the record
}

connect(view, SIGNAL(clicked(const QModelIndex&)), this, SLOT(recordSelected()));

//then
void MainWindow::recordSelected()
{
   QModelIndex index = view->currentIndex();
   QSqlRecord record;
   int i = index.row(); // now you know which record was selected
   record = model->record(i);
// and I do something with the record
}

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So what do you need the button for then?

[saa7_go]

maybe, subclassing QTableView can achieve what you want.

tableview.h :

#ifndef TABLEVIEW_H
#define TABLEVIEW_H
 
#include <QTableView>
 
class TableView : public QTableView
{
    Q_OBJECT
public:
    TableView(QWidget *parent = 0);
 
protected:
    void selectionChanged(const QItemSelection &selected, const QItemSelection &deselected);
 
signals:
    void rowSelected(int row_num);
    void rowSelected(bool val);
};
 
#endif // TABLEVIEW_H

#ifndef TABLEVIEW_H
#define TABLEVIEW_H

#include <QTableView>

class TableView : public QTableView
{
    Q_OBJECT
public:
    TableView(QWidget *parent = 0);

protected:
    void selectionChanged(const QItemSelection &selected, const QItemSelection &deselected);

signals:
    void rowSelected(int row_num);
    void rowSelected(bool val);
};

#endif // TABLEVIEW_H

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tableview.cpp :

#include "tableview.h"
#include <QItemSelection>
#include <QHeaderView>
 
TableView::TableView(QWidget *parent) : QTableView(parent)
{
}
 
void TableView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
{
    QTableView::selectionChanged(selected, deselected);
 
    if(model() != 0)
    {
        if(selectedIndexes().count() == 0)
        {
            emit rowSelected(false);
            return;
        }
 
        int count = 0;
        int row = selectedIndexes().at(0).row();
 
        foreach(QModelIndex m, selectedIndexes()) {
            if(m.row() == row)
                count++;
            else
                return;
        }
 
        if(count == horizontalHeader()->count())
        {
            emit rowSelected(true);
            emit rowSelected(row);
        }
        else
        {
            emit rowSelected(false);
        }
    }
}

#include "tableview.h"
#include <QItemSelection>
#include <QHeaderView>

TableView::TableView(QWidget *parent) : QTableView(parent)
{
}

void TableView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
{
    QTableView::selectionChanged(selected, deselected);
    
    if(model() != 0)
    {
        if(selectedIndexes().count() == 0)
        {
            emit rowSelected(false);
            return;
        }

        int count = 0;
        int row = selectedIndexes().at(0).row();

        foreach(QModelIndex m, selectedIndexes()) {
            if(m.row() == row)
                count++;
            else
                return;
        }

        if(count == horizontalHeader()->count())
        {
            emit rowSelected(true);
            emit rowSelected(row);
        }
        else
        {
            emit rowSelected(false);
        }
    }
}

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main.cpp :

#include <QApplication>
#include <QPushButton>
#include <QVBoxLayout>
#include <QFileSystemModel>
#include "tableview.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
 
    QWidget w;
    QVBoxLayout *lay = new QVBoxLayout(&w);
    QPushButton *button = new QPushButton("Go");
    button->setEnabled(false);
 
    TableView *v = new TableView;
    QFileSystemModel model;
    model.setRootPath("C:/");
    v->setModel(&model);
 
    lay->addWidget(v);
    lay->addWidget(button);
 
    QObject::connect(v, SIGNAL(rowSelected(bool)), button, SLOT(setEnabled(bool)));
    w.show();
 
    return app.exec();
}

#include <QApplication>
#include <QPushButton>
#include <QVBoxLayout>
#include <QFileSystemModel>
#include "tableview.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QWidget w;
    QVBoxLayout *lay = new QVBoxLayout(&w);
    QPushButton *button = new QPushButton("Go");
    button->setEnabled(false);

    TableView *v = new TableView;
    QFileSystemModel model;
    model.setRootPath("C:/");
    v->setModel(&model);

    lay->addWidget(v);
    lay->addWidget(button);

    QObject::connect(v, SIGNAL(rowSelected(bool)), button, SLOT(setEnabled(bool)));
    w.show();

    return app.exec();
}

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[scarleton]

Well, that works for me as long as I click in a cell.

I am calling the little box to the LEFT of the first cell, where the table displays the row number, the "row header". When I click on this "row header", the slot is never called. I played around a bit more and discovered that selectionBehavior was set to QAbstractItemView::SelectRows. When I changed it to QAbstractItemView::SelectItems, then it was not possible to select the "row header".

I want to differentiate between clicking on a cell in a row and selecting the whole row. Is that possible?

Sam

[norobro]

Take a look at the signals emitted by QHeaderView.
For instance, you could connect QTableView::verticalHeader()->sectionPressed() to a slot that enables your button.

[saa7_go]

how about connecting the vertical header view to your slot?

for example:

connect(tableView->verticalHeader(), SIGNAL(sectionClicked(int)), this, SLOT(yourCustomSlot(int)));

connect(tableView->verticalHeader(), SIGNAL(sectionClicked(int)), this, SLOT(yourCustomSlot(int)));

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[scarleton]

Thank you, that was it, getting the signal off the header.